The role of fluid flow in the dynamics of active nematic defects
The role of fluid flow in the dynamics of active nematic defects
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DOI：
10.1088/1367-2630/abe8a8
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发表时间：
2021-03-01
影响因子：
3.3
通讯作者：
Bowick, Mark J.
中科院分区：
文献类型：
--
作者：
Angheluta, Luiza;Chen, Zhitao;Bowick, Mark J.
我们适应Halperin-Mazenko形式主义来分析二维主动向列相耦合到一个通用的流体流动。控制流体动力学方程导致的演化规律的拓扑缺陷和它们相应的密度场。我们发现+/- 1/2缺陷是由局部流体流动以及与流动剪切速率相结合的向列取向推动的。在过阻尼和可压缩的限制，我们恢复了先前获得的主动自推进的+1/2缺陷。非局部流体动力学效应主要对不可压缩流动是重要的，对于不可压缩流动，不可能仅为了局部缺陷极化而消除流体速度。对于电荷相反的两个缺陷的情况下，非局部流体动力学相互作用介导的非互易的压力梯度力。最后，我们推导出耦合到任意（可压缩或不可压缩）流体流的缺陷气体的连续方程。
We adapt the Halperin-Mazenko formalism to analyze two-dimensional active nematics coupled to a generic fluid flow. The governing hydrodynamic equations lead to evolution laws for nematic topological defects and their corresponding density fields. We find that +/- 1/2 defects are propelled by the local fluid flow and by the nematic orientation coupled with the flow shear rate. In the overdamped and compressible limit, we recover the previously obtained active self-propulsion of the +1/2 defects. Non-local hydrodynamic effects are primarily significant for incompressible flows, for which it is not possible to eliminate the fluid velocity in favor of the local defect polarization alone. For the case of two defects with opposite charge, the non-local hydrodynamic interaction is mediated by non-reciprocal pressure-gradient forces. Finally, we derive continuum equations for a defect gas coupled to an arbitrary (compressible or incompressible) fluid flow.